If cheap enough you might source a sunroof panel at a pick and pull type of operation. I do not think the paint should have separated like it has even with a bend.

Cracked etc. I would have understood. If there is no factory primer left under the lifted paint portion it may not have been a repaint fault.

Just poor adhesion of the original primer in general. Or if there had been some rust in that area before the repaint. They may not have prepped the bare metal properly after removing the rust in that area before respraying.